Accelerating LLM Inference 3x with Speculative Decoding and vLLM

Pair small draft models with large target models to triple output token throughput without altering output probabilities.

Prerequisites

Linux terminal
vLLM
NVIDIA GPU

Step 1: Step 1: The Mathematics of Speculative Verification

A lightweight 1B draft model guesses multiple candidate tokens in parallel; the large 70B model verifies all candidates in a single forward pass.

Step 2: Step 2: Deploying vLLM with Speculative Draft Engine

Configure vLLM arguments `--speculative-model` to achieve immediate latency reduction for interactive user experiences.